<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>三元表达式</title>
</head>
<body>
    <script>
        // 要求 用户输入名字 如果小于10 则在前面补0 比如 01 09  大于10 则不用补
        var num = prompt('请输入您的数字');
        var result = num < 10 ? '0' + num : num ;
        console.log(result);
        alert(result);
    </script>
</body>
</html>